A bunch of people helped read Lessig's Free Culture. I know Raph Levien was one of them, and he also has a couple of other audio books on his homepage at http://raph.levien.com/audiobook/ .

Dissatisfied with the quality of PG's text2speech, I tried to measure the interest of the subscribers to PG's volunteer mailing list for producing human read audio books. Although some people thought it might be a good idea, I don't think anybody ever did anything with that.